1. I'm sorry, _________ I won't be able to come tonight.
A. for B. and C. but D. then
【陷阱】容易误选A,因为空格后的句子是用以说明 I'm sorry 的原因的,所以便想当然地认为要选for来表示原因。
【分析】事实上,I'm sorry 后习惯上不接表示原因的连词for后习惯上不接表示原因的连词,而接表示转折的连词but(也可省略 but),用以委婉地提出一个使对方不快的事实。又如:
Oh, sorry, but she's out. 哦,不好意思,她出去了。
I'm sorry, but I have to disagree. 对不起,我不敢苟同。
I'm sorry, but I have already had another appointment. 对不起,我已经有约会了。
注:I'm sorry 后虽然不能接表原因的连词for,但却可接介词 for。如:
I'm sorry for shouting at you. 对不起冲你嚷嚷了。
I am sorry for what I said to you. 我后悔不该对你讲那些话。

2. The point is not who said the words, _________ they are true or not.
A. but whether B. and whether C. but how D. and how
【陷阱】几个干扰项均有可能误选。
【分析】最佳答案为A。此题涉及两个搭配:一是 not ... but ...(不是……而是……),二是 whether ... or not (是否)。请看类例:
He was not an actor, who often appeared on stage, _________ a writer, writing stories.
A. but B. and  C. then D. so
答案选A,主要考查 not ... but ... 结构。

3. Just because they make more money than I do, _________ they seem to look down on me.
A. so B. and C. but D. 不填
【陷阱】但容易误选A,将汉语的"因为……所以……"直译为 because ... so ...。
【分析】此题正确答案为D,但是按英语语法,because 为从属连词,用以引导原因状语从句,它表明整个句子为复合句;而 so 在表示"所以"时,它是并列连词,用以连接两个简单句使之成为并列句。由于在同一句中既用了从属连词 because,又用了并列连词 so,使得该句一半像复合句,一半像并列句,从而导致错误。正确的做法是,任意去掉 because 和 so 中的一个,使之要么成为复合句,要么成为并列句。
4. Although he had only entered the contest for fun, _________ he won first prize.
A. but B. and C. even D. 不填
【陷阱】容易误选A,将汉语的"虽然……但是……"直译为 although ... but ...。
【分析】正确答案选D。按英语语法,although 为从属连词,用以引导让步状语从句,它表明整个句子为复合句;而although but 在表示"但是"时,它是并列连词,用以连接两个简单句使之成为并列句。由于在同一句中既用了从属连词 although,又用了并列连词 but ,使得该句一半像复合句,一半像并列句,从而导致错误。正确的做法是,任意去掉 although ,使得该句一半像复合句,一半像并列句,从而导致错误。正确的做法是,任意去掉和 but 中的一个,使之要么成为复合句,要么成为并列句。其实,此题与上面一题的分析思路是一样的。这里顺便说一句,许多同学(包括许多老师和教学参考书)为了便于记忆,将此题与上面一题的知识点简单地归纳为"按英语习惯,because和so不可连用,although 与 but 与不可连用"。这种说法在通常情况下无疑是对的,也是有效的,但同学们一定要在明白以上道理的情况下来使用此规则,如果只是死记该规则,有时遇到一些语言特例仍然会出错。如:
But I didn't know that then, although I learned it later. 但我当时的确不知道此事,尽管后来我还是知道了。
此句既用了并列连词 but,又用了从属连词 although,但它并未造成错误,原因是此句与上面所讨论的情形有所不同, although but 用于 although 之前,but 在此仅起到与上文转折的作用,but 后的 I didn't know that then, although I learned it later. 仍为一个复合句。
I tried doing the accounts, but although I knew some maths I found it very difficult. 我试着算这些账,但尽管我懂点数学,仍感到很困难。
此句将 but 与 although 用在一起,但此句也没有错误。该句从总体来看,它是一个以并列连词 but 连接的并列句,而在该并列句的后面一句又是一个包含让步状语从句 although I knew some maths 的复合句--这种句型就是所谓的并列复合句。此句也可改写为 I tried doing the accounts, but I found it very difficult although I knew some maths.

5. When the last prize had been awarded _________ everybody cleared off.
A. and B. so C. or D. 不填
【陷阱】容易想当然地误选A。
【分析】句首 when 引导的是一个时间状语从句,它暗示整个句子为复合句;而so, and, or 为并列连词,无论选哪一个,都表明整个句子为并列句,从而导致前后矛盾,所以A、B、C均不能选择。此题正确答案选D,everybody cleared off 为整个复合句的主句。请看类似例子:
(1) If wishes were horses, _________ beggars would ride.
A. and B. so C. or D. 不填
(2) If I'm mistaken, _________ you are mistaken too.
A. so B. and C. or D. 不填
(3) Just before I left London, _________ I sent him a telegram.
A. and B. so C. or D. 不填
(4) After they had each said a few words, _________ Lloyd George took the floor.
A. and B. so C. or D. 不填答案
均选D,空格前分别为 if, when, before, after 引导的状语从句,空格后为整个复合句的主句。